Active stereo matching for depth applications

A head-mounted device (HMD) configured for performing geometric surface reconstruction in conjunction with head tracking, the HMD comprising:

• a head tracking stereo camera pair comprising a first camera and a second camera which are both mounted on the HMD, wherein:
• a part of a field of view of the first camera overlaps with a part of a field of view of the second camera to form an overlapping region;
• and
• both of the first camera and the second camera are configured to detect both visible light and infrared (IR) light;
• an IR dot-pattern illuminator mounted on the HMD and configured to emit an IR dot-pattern illumination that spans an illumination area that overlaps at least a part of the overlapping region;
• one or more processors;
• and
• one or more computer-readable hardware storage devices having stored thereon computer-executable instructions, the computer-executable instructions being executable by the one or more processors to cause the HMD to:
• at a first selected frame rate, perform at least the following:
• use the head tracking stereo camera pair to obtain visible light images of a surrounding environment of the HMD;
• and
• use the visible light images of the surrounding environment to track a position of the HMD within the surrounding environment;
• and
• at a second selected frame rate, perform at least the following:
• cause the IR dot-pattern illuminator to emit an IR dot-pattern illumination onto at least a part of the surrounding environment;
• cause the head tracking stereo camera pair to sense reflected IR light which is reflected as a result of the IR dot-pattern illumination being emitted onto at least the part of the surrounding environment;
• calculate a depth map using stereo depth imaging, the depth map being based on the reflected IR light and visible light captured by the head tracking stereo camera pair;
• and
• construct a geometric surface for at least the part of the surrounding environment using the depth map.